The clownfish can be many different colors, depending on its species, including yellow, orange, red, and black. Most have white details. They are smaller fish, with the smallest around 7 to 8cm long and the longest 17cm long. Clownfish are found in warm waters, such as the Red Sea and Pacific Oceans, in sheltered reefs or lagoons, living in anemone. Clownfish eat various small invertebrates and algae, as well as food scraps the anemone leaves behind.  

This oval-shaped tropical reef fish is a popular aquarium and bait fish that has three color phases of its life. It isn’t often consumed because of the strong odor and chance of ciguatera poisoning. Handle with care if catching because of the sharp spine hidden in the caudal peduncle (narrow area just before the tail). These vegetarians play an important role on the reefs by eating the algae that can grow over the coral and kill it.

 Lionfish have distinctive brown or maroon, and white stripes or bands covering the head and body. They have fleshy tentacles above their eyes and below the mouth; fan-like pectoral fins; long, separated dorsal spines; 13 dorsal spines; 10-11 dorsal soft rays; 3 anal spines; and 6-7 anal soft rays. An adult lionfish can grow as large as 18 inches, while juveniles may be as small as 1 inch or less.  The range of the lionfish covers a very large area from western Australia and Malaysia east to French Polynesia and the United Kingdom's Pitcairn Islands.

If fish were like cars, tuna would be the Ferraris of the ocean—sleek, powerful, and made for speed. Their torpedo-shaped bodies streamline their movement through water, and their special swimming muscles enable them to cruise the ocean highways with great efficiency. Tuna are remarkable and impressive wild animals. The Atlantic bluefin can reach ten feet in length and weigh as much as 2,000 pounds (more than a horse). Their specialized body shape, fins, and scales enable some species of tuna to swim as fast as 43 miles per hour.

Seahorses may sound like mythical creatures but here you can see just how real they are! In this kingdom Seahorses grip at seagrass with their curly tails and suck up tiny shrimp with their straw-like snouts. Male seahorses, seadragons and pipefish are the only male animals to give birth!

Despite their snake-like appearance, moray eels are actually fish. All moray eels have one long fin that extends from the head to the tail. Because it looks quite ferocious, the moray eel has long had a fearsome reputation. Roman legend tells of Nero throwing slaves into watery pits filled with moray eels so bored aristocrats could view people being eaten alive. While it is a reputation that moray eels find hard to live down, they are not aggressive animals and will attack only when threatened. At least 15 different species live in north-western Australia.

The electrocytes of most 'electric fishes' are modified muscle cells. Electrocytes are usually arranged in columns within electric organs. This arrangement increases the electrical output, much like a row of batteries placed end to end. The electric organs of the torpedo rays contain about 45 columns of around 700 electrocytes. Electrical discharges escape through the dorsal surface of the fish. This is because the dorsal surface of both the electric organ and the body have less resistance than the surrounding tissues.

Whale sharks (Rhincodon typus) are the largest shark, and indeed largest of any fishes alive today. They feed on plankton and travel large distances to find enough food to sustain their huge size, and to reproduce. Whale sharks are found in all the tropical oceans of the world. Their white spotted colouration makes these gentle giants easy to distinguish, and popular with snorkelers and divers at sites where they aggregate off the coast.

The great white shark is the world's largest known predatory fish. It has 300 teeth, yet does not chew its food. Sharks rip their prey into mouth-sized pieces which are swallowed whole. The shark’s heavy, torpedo-shaped body allows it to cruise efficiently for long periods of time, and then suddenly switch to high speed bursts in pursuit of prey—sometimes leaping out of the water. It feeds on a broad spectrum of prey, from small fish, such as halibut, to large seals and dolphins.

Three species of hammerhead shark are found in north-western Australia but only one, the great hammerhead (Sphyrna mokarran), is considered dangerous. The scalloped hammerhead (Sphyrna lewini) and smooth hammerhead (Sphyrna zygaena) are quite timid and the similar-looking winghead shark (Eusphyra blochii) is considered harmless. Despite the fear they have traditionally engendered, these days, most divers who see a hammerhead shark regard it as a rare and exciting experience.

The giant manta ray is the world’s largest ray with a wingspan of up to 26 feet. They are filter feeders and eat large quantities of zooplankton. Giant manta rays are slow-growing, migratory animals with small, highly fragmented populations that are sparsely distributed across the world.

The common octopus would be unique for its appearance alone, with its massive bulbous head, large eyes, and eight distinctive arms. But by far the most striking characteristic of the octopus is the wide array of techniques it uses to avoid or thwart attackers.

Squid also come in all sizes: from pygmy squid that are the size of a pinky fingernail to giant squid which may reach as many as 59 feet long—which is perhaps why this gigantic beast inspired the legend of the Kraken. However, while the oldest known example of a squid-like creature attacking prey dates back nearly 200 million years, squid are not known to hunt humans, or sink ships.

These cephalopods (which means “head foot”) have eight arms and two long tentacles attached directly to their head. The mantle—the area behind the eyes which contains the cuttlefish’s internal organs—is surrounded by a fringe-like fin that flaps in a rippling motion for maneuvering.

Lacking brains, blood, or even hearts, jellyfish are pretty simple critters. They are composed of three layers: an outer layer, called the epidermis; a middle layer made of a thick, elastic, jelly-like substance called mesoglea; and an inner layer, called the gastrodermis. An elementary nervous system, or nerve net, allows jellyfish to smell, detect light, and respond to other stimuli. The simple digestive cavity of a jellyfish acts as both its stomach and intestine, with one opening for both the mouth and the anus.

 Anemones are beautiful marine animals with wavy tentacles, and resemble underwater flowers. They are usually brightly coloured, adopting shades of white, green, blue, orange, red or mauve, often contributing to the spectacular walls of invertebrates populating reefs. Species such as the bulb-tentacled sea anemone (Entacmaea quadricolor) and magnificent sea anemone (Heteractis magnifica) form homes for beautiful anemonefish or clownfish, which shelter from predators in the anemone’s stinging cells. Certain species of sea anemones are thought to be able to survive for 100 years or more.

Sea stars live underwater, but that is where their resemblance to fish ends. They do not have gills, scales, or fins. Sea stars live only in saltwater. Sea water, instead of blood, is actually used to pump nutrients through their bodies via a 'water vascular system.'

Also, sea stars move by using tiny tube feet located on the underside of their bodies. Adult sunflower sea stars can move at the astonishing speed of one meter per minute using 15,000 tube feet. Tube feet also help sea stars hold their prey.

Sea urchins belong to a family called Echinodermata; a term that means spiny-skinned. This Phylum is also home to the likes of starfish, brittle stars and sea cucumbers. As a group, these animals are all known as echinoderms.

As they are spherical in shape and often live on the ocean floor, it’s easy to see why they might be seen as a plant, but they are in fact invertebrates. Sea urchins have been around for 450 million years, making them older than dinosaurs!

The blue whale is the largest animal on the planet, weighing as much as 200 tons (approximately 33 elephants). The blue whale has a heart the size of a Volkswagen Beetle. Its stomach can hold one ton of krill and it needs to eat about four tons of krill each day. They are the loudest animals on Earth and are even louder than a jet engine.

Orcas, or killer whales, are the largest of the dolphins and one of the world's most powerful predators. They're immediately recognizable by their distinctive black-and-white coloring. Smart and social, orcas make a wide variety of communicative sounds, and each pod has distinctive noises that its members will recognize even at a distance. They use echolocation to communicate and hunt, making sounds that travel underwater until they encounter objects, then bounce back, revealing their location, size, and shape.

Sea otters are a keystone species, meaning they help keep their ecosystems in balance. In particular, sea otters keep kelp forests healthy by eating sea urchins and other invertebrates that graze on giant kelp. If sea otters disappeared, their ecosystems would become unbalanced and unhealthy. Urchins would strip the kelp beds that many species depend on for food, shelter and nurseries.

California sea lions are known for their intelligence, playfulness and noisy barking. Their fur color ranges from chocolate brown seen in males to a lighter, golden brown seen in females. Another key difference between males and females is that male sea lions are much larger—reaching up to 600 to 850 pounds and 7 feet in length. Females grow to 200 to 250 pounds and up to 6 feet in length.

Manatees are usually seen alone, in pairs, or in small groups of a half dozen or fewer animals. From above the water's surface, the animal's nose and nostrils are often the only thing visible. Manatees never leave the water but, like all marine mammals, they must breathe air at the surface. A resting manatee can remain submerged for up to 15 minutes, but while swimming, it must surface every three or four minutes.

Seven different species of sea (or marine) turtles grace our ocean waters, from the shallow seagrass beds of the Indian Ocean, to the colorful reefs of the Coral Triangle and the sandy beaches of the Eastern Pacific. While these highly migratory species periodically come ashore to either bask or nest, sea turtles spend the bulk of their lives in the ocean. WWF's work on sea turtles focuses on five of those species: green, hawksbill, loggerhead, leatherback, and olive ridley.

The leafy sea dragon (Phycodurus eques) is one of three species of sea dragon found only in Australian waters and nowhere else in the world. the others being the weedy sea dragon and the ruby sea dragon. Despite its fearsome name, it is incredibly beautiful in shape and colouring and its camouflaging appendages give it a fragile appearance. It is a relative of the seahorse and belongs to the pipefish family Sygnathidae.

A sea angel is a type of swimming snail. The muscular foot found in land snails has evolved into a pair of winglike structures called parapodia that are used for swimming in open water. Sea angels have a small, transparent, gelatinous body and do not have a shell.